Bio-Rad Criterion Dodeca Cell User Manual

Criterion®Dodeca

™

Cell

Instruction Manual

Catalog Number

165-4130

For Technical Service Call Your Local Bio-Rad Office or in the U.S. Call 1-800-4BIORAD (1-800-424-6723)

Table of Contents

Page

Section 1 General Information....................................................................................1

1.1 Introduction ................................................................................................................1

1.2 Safety ..........................................................................................................................1

1.3 Components................................................................................................................2

Section 2 Setting up the Dodeca Cell for Electrophoresis ........................................3

2.1 Preparing the Buffers .................................................................................................3

2.2 Preparing the Criterion Precast Gel ...........................................................................4

2.3 Assembling the Cell ...................................................................................................4

2.4 Opening Criterion Cassettes and Removing the Gel.................................................6

2.5 Accessories for Cooling .............................................................................................7

Section 3 Maintenance .................................................................................................8

3.1 General Maintenance .................................................................................................8

3.2 Draining the Tank.......................................................................................................8

3.3 Guidelines for Reusing Tank Buffer..........................................................................8

Section 4 Troubleshooting Guide ................................................................................9

Section 5 Product Information and Accessories .....................................................10

Section 6 Warranty Information...............................................................................11

Section 1
General Information

1.1 Introduction

The Criterion Dodeca Cell is a multi-cell for mini-vertical gel electrophoresis. It can run

one to twelve Criterion gels simultaneously.

Table 1. Specifications

Tank and lid Acrylic
Upper electrode assembly Polycarbonate with 241 cm, (95 inches) platinum

wire

Lower electrode assembly Polycarbonate with 201 cm (79 inches) platinum

wire

Drain line Tygon

1

tubing

Drain line connectors Delrin

2

Cooling coil Acrylic
Cooling coil connector tubing Tygon
Total buffer volume 6 liters maximum (running one gel),

(upper and lower buffer 5.34 liters minimum (running 12 gels)
chambers combined)

Overall size 49 cm (L) x 18.8 cm (W) x 19.2 cm (H)
Precast gel compatibility Criterion precast gels
Handcast gel compatibility Gels prepared in empty Criterion cassettes
Recommended power supply PowerPac 200 power supply
Safety limits 600 V, 250 W
Weight 4.66 kg (10.25 lb)

Note: Dodeca Cell components are not compatible with acetone or ethanol. Use of organic
solvents voids all warranties.

1.2 Safety

Power to the Criterion Dodeca Cell is supplied by an external DC voltage power supply
(not included). The output of the power supply must be isolated from external ground to insure
that the DC voltage output floats with respect to ground. All Bio-Rad power supplies meet this
important safety requirement. Regardless of the power supply used, the maximum specified
operating parameters for the Criterion Dodeca Cell are as follows:

600 VDC voltage limit
250 watts power limit
40 °C ambient temperature limit

The current to the cell enters the unit through the lid assembly that provides a safety­interlock to the user. The current to the cell via the lid’s upper electrodes is broken when the
lid is removed. Always turn off the power supply before removing the lid. Do not attempt to

use the cell without the safety lid.

1

Tygon is a registered trademark of Norton Co.

2

Delrin is a registered trademark of E.I. DuPont de Nemours.

1

2

Note: This Bio-Rad instrument is designed for laboratory use only and is certified to meet
EN-61010 safety standards. Operation of this product is subject to the condition that no harmful
radio interference is caused and that any interference must be accepted. Certified products
are safe to use when operated in accordance with the instruction manual. This instrument
should not be modified or altered in any way. Alteration of this instrument will

• Void the warranty

• Void the EN61010-1 certification, and

• Create a potential safety hazard

Bio-Rad is not responsible for any injury or damage caused by use of this instrument for
purposes other than those for which it is intended or by modifications of the instrument not
performed by Bio-Rad or an authorized agent.

*

EN61010-1 is an internationally accepted electrical safety standard for laboratory instruments.

1.3 Components

To get the best performance from your Criterion Dodeca Cell, familiarize yourself with
the components by assembling and disassembling the cell before using it for the first time.

Criterion Dodeca Cell tank.

Criterion Dodeca Cell lid with power cables.

Cooling coil

Buffer overfill
drain ports

Male banana
plugs

Cassette-opening
tool

Buffer drain port

Gel cassette
orientation label

Drain port cover

Color-coded
power cables

Upper electrode
assembly (cathode)

Buffer fill
level label

Lower electrode
assembly (anode)

Female quick­connectors
for coolant
recirculation

Table 2. Description of Parts

Buffer tank and lid The buffer tank and lid combine to fully enclose the

inner chamber during electrophoresis. The lid cannot
be removed without disrupting the electrical circuit.
The buffer fill level and gel cassette orientation are
indicated with labels.

Cooling coil The integrated cooling coil chills the lower buffer

chamber. The cooling core can be connected to a
refrigerated circulator (not included).

Electrode assembly The lower buffer chamber (tank) contains the anode.

The lid of the Dodeca Cell houses the cathode.

Drain port The drain port allows buffer to be removed from the

tank. The drain line attaches via a quick-connect
fitting (this assembly is provided with the cell). The
buffer drains by gravity out from the open end of
the drain line into an appropriate-size vessel. To
ensure safety, the cell cannot be drained while the
lid is on.

Buffer overfill drain ports For user safety, buffer overfill drain ports do not

allow the buffer level to reach the upper electrode
assembly and create a dangerous short condition
within the cell.

Gel cassette A Criterion precast gel or a handcast gel in a

Criterion cassette is referred to as a gel cassette.

Cassette-opening tool The cassette-opening tool is a wedge built into the

tank. It offers a convenient way to crack open gel
cassettes after electrophoresis.

Section 2
Setting Up the Dodeca Cell for Electrophoresis

2.1 Preparing the Buffers

Prepare 6 liters of running buffer for electrophoresis. Buffer may be chilled prior to
electrophoresis. If the SDS precipitates out of the buffer, insure it is completely redissolved
before electrophoresis.

Table 3. Standard Running Buffer Formulations

Tris/Glycine/SDS 25 mM Tris-Base (M.W. 121.1),

192 mM Glycine (M.W. 75.07),

0.1% SDS,
pH 8.3, (Do not adjust the pH with acid or base. If

the pH is not accurate remake the buffer).

Tris/Tricine/SDS 100 mM Tris-Base (M.W. 121.1),

100 mM Tricine (M.W. 179.2),

0.1% SDS,
pH 8.3, (Do not adjust the pH with acid or base. If

the pH not accurate remake the buffer).

Tris/Boric Acid/EDTA (TBE) 89 mM Tris-Base (M.W. 121.1),

89 mM boric acid (M.W. 61.83)
2 mM EDTA (M.W. 372.26),
pH 8.3, (Do not adjust the pH with acid or base. If

the pH is not accurate remake the buffer).

3

Tris/Acetic Acid/EDTA (TAE) 40 mM Tris,

20 mM acetic acid,
1 mM EDTA,
pH 8.0

Premixed buffers are available (see Section 4.) Dilute the premixed 10x buffers (10x
Tris/Glycine/SDS, 10x Tris/Glycine, 10x Tris/Tricine/SDS, 10x TBE, and 50x TAE) to a
working concentration of 1x. Mix one liter of the premixed 10x buffer with 9 liters of distilled
water to prepare 10 liters of running buffer.

2.2 Preparing the Criterion Precast Gel

All gels in a single electrophoresis experiment must be of the same gel type, with the
same buffer and the same % acrylamide.3Complete instructions for Criterion precast gels
may be ordered using catalog number 345-0000. Instructions are also available on the
internet at www.discover.bio-rad.com in the precast gels literature section (bulletin 4110001).

a. Each Criterion gel is packaged individually in a plastic storage tray. Remove the cover by

gently pulling the square corner tab up and diagonally across the package. Remove the gel

cassette from the package.

b. Remove the comb and gently rinse the wells with dd H20 or running buffer.

c. Remove the white tape from the bottom of the cassette by pulling the tab across the gel.

2.3 Assembling the Cell

a. Place the Dodeca Cell on a stir plate. Fill the tank half full and drop a 38 mm (1.5") stir bar

into the buffer tank. (This step must be done prior to loading the cassettes into the cell.)

Inserting Criterion gel cassette into tank.

b. Insert each Criterion gel into one of the slots in the Criterion Dodeca Cell. Ensure that the

integral buffer chamber is facing the chiller hook-ups. Gel cassette orientation is indicated

with a label on the tank.

c. Fill the upper buffer chamber of each cassette with approximately 60 ml buffer.

3

If running gels with different buffers or % acrylamide, the run progress should be monitored closely and gels can be removed as
neccessary.

4

d. Load samples with a Hamilton syringe or a pipette with gel loading tips. Alternatively, use

the sample loading guide to align the pipet tip with the sample wells.

Note: If sample diffusion is of concern during loading, 2 or 3 gels may be loaded outside
the tank and then transferred into the tank to be run under very low voltage (10–20 volts).
Then the next 2 or 3 gels may be loaded and inserted into the tank and run at 10–20 volts. This
process is continued until all gels are loaded and ready to run. Buffer levels in both the upper
and lower chambers should be checked to insure they are appropriate.

e. Fill tank to the Fill Level line indicated on the tank. See Table 1 for total buffer volumes.

Tank sitting on stir plate

f. Place the lid on the tank, aligning the color-coded banana plugs and jacks. It is easiest to

align the side with the banana plugs and drain cover first and then slide the lid down in

to place.

Placing lid on tank

g. Set the power supply to recommended conditions and start the run. See Table 4 for

recommended running conditions.

5

Stir bar

Align this side first,
then slide down to fit.

Table 4. Running Conditions (for 12 Criterion precast gels, 1.0
mm thickness)

Gel and Buffer Voltage Initial Current Final Current Run Time

System (approximate) (approximate) (approximate)

Tris-HCl 200 V 1.0–1.4 A 400–500 mA 56 minutes

Tris/Glycine/SDS
or Tris/Glycine

The PowerPac 200 power supply will be limited at maximum power of 200W for a few minutes
(5–10 minutes) at this time the voltage will read less than the indicated voltage setting (about 180 V).
The Bromophenol Blue dye was run to the bottom of the gel.

Tris-Tricine 125 V 1.6 A 850 mA 110 minutes
Tris/Tricine/SDS

The PowerPac 200 power supply will be limited at maximum power of 200W for a few minutes
(20 minutes) at this time the voltage will read less than the indicated voltage setting (about 115 V).

TBE 200 V 500 mA 400 mA 76 minutes
Tris/Boric
Acid/EDTA

The gels were run until the first dye (Bromophenol Blue) cleared the gel.

TBE-Urea 200 V 500 mA 250 mA 76 minutes
Tris/Boric
Acid/EDTA

The gels were run until the second dye (Xylene Cyanole) was at the very bottom of the gel, the first
dye (Bromophenol Blue) was run off the gel

Note: Precast and Tris-Tricine gels will run slightly warmer then handcast, Tris-HCl and
TBE gels. Precast gels are prepared with Tris-HCl pH 8.6 and most handcast gels are cast
using Tris-HCl pH 8.8, this minor variation will alter the run times slightly, precast gels will
run a little faster.

2.4 Opening Criterion Cassettes and Removing the Gel

a. After electrophoresis is complete, turn off the power supply and disconnect the electrical

leads.

b. Remove the cell from the stir plate. Be sure to pick up the tank from the bottom. Remove

the lid from the tank.

c. Remove the gel cassette. Pour off and discard the buffer from the Integral Buffer Chamber.

Note: If the lower buffer will be reused, do not pour the depleted buffer from the integral

upper buffer chamber into the tank. The lower buffer can be reused up to 10 times depending

on usage (see guidelines in Section 3).

6

d. Invert the cassette and place the end of the Integral Buffer Chamber of the gel cassette on

the cassette-opening tool which is built into the Criterion Dodeca Cell tank. Holding the

cassette upside down with two hands, position one end of the integral buffer chamber

directly over the top of the wedge protrusion on the tank. Firmly press down on the

cassette to crack the cassette weld. Repeat for the other end of the integral buffer chamber.

First crack the weld on one side. Then crack the weld on the other side.

Note: Be careful not to squeeze the cassette in the middle. This may cause distortions or
other damage to the gel.

Do NOT squeeze the gel cassette in the middle.

e. Pull the two halves of the cassette apart to completely expose the gel. Be careful, the gel

may partially stick to both sides. Open slowly to avoid tearing the gel.

f. Remove the gel by either floating the gel into a fixing or staining solution, or by carefully

lifting the gel from the cassette while holding the bottom of the gel.

g. Repeat c–f for each gel in the tank.

2.5 Accessories for Cooling

The Criterion Dodeca Cell has a cooling coil with quick connect fittings that can be
connected to a refrigerated circulator. The refrigerated circulator must be able to maintain
the buffer temperature of 18 to 20 ºC in the tank during electrophoresis.

4

Tubing with 3/8" ID
(not included) connects the Dodeca Cell to the refrigerated circulator. To connect the Dodeca
Cell to the refrigerated circulator,

a) Insert the male fittings (supplied in a separate bag) into the tubing on the refrigerated

circulator inlet and outlet tubing.

4

For example, the refrigerated circulator used during development of the Dodeca Cell was set to 15 ºC and had a flow rate of 3.8 liters
per minute. Under these conditions and using the recommended volume of buffer, the buffer temperature during electrophoresis was
maintained at 18 to 20 ºC.

7

b) Connect the male fittings from the refrigerated circulator to the female fittings on the

Criterion Dodeca Cell. The cooling coil in the Dodeca Cell has no specific orientation, so
it is not important which direction the flow goes.

A refrigerated circulator is not required for running Tris-HCl, TBE and TBE-Urea gels
because the large volume of buffer serves as a sufficient heat sink. However, a refrigerated
circulator is recommended to maintain a set temperature while running a large number of
Tris-Tricine gels since they produce more heat during electrophoresis. Nonetheless, the
cooling option offers additional control over the running conditions when desired.

Note: The Dodeca Cell MUST be used with a stir bar and stir plate. Stirring the buffer is
essential in maintaining a constant buffer temperature throughout the entire cell. Without this
control, the run times between the twelve gels in the tank may vary, thus altering the
migration patterns of the samples from gel to gel.

Section 3
Maintenance

3.1 General Maintenance

The Criterion Dodeca Cell lid should be rinsed after use. The tank should be rinsed
thoroughly each time it is emptied.

3.2 Draining the Tank

To drain the tank, insert the male quick-connect fitting into the drain port on the end of
the tank and allow to drain by gravity. Be sure that the open end of the tubing is placed into
a receptacle of the appropriate size, since buffer will flow out as soon as the connection is
made. Alternatively, pick up the entire tank and pour off the buffer.

3.3 Guidelines for Reusing Tank Buffer

The buffer in the lower tank may be reused up to 10 times. Sodium azide (final concentration
of 0.02%) is recommended to help minimize contamination.

The number of times the buffer is used depends on the number of gels run each time and
the conditions at which the runs are performed. The primary concern is ion depletion. Prepare
fresh buffer if the following problems appear:

• changes in protein mobility

• decrease in band sharpness

• longer run times

• a band at the bottom of the gel which is difficult or impossible to destain

8

Section 4
Troubleshooting Guide

Problem Cause Solution

1 Smile effect – band a. Center of the gel running a. Improper cooling. Ensure

pattern curves upward at hotter than either end buffer level is to the fill
both sides of the gel line indicated on the tank.

Use cooling coil and
refrigerated circulator to
maintain buffer temperature
of 20 ºC

b. Power conditions are b.Decrease voltage from 200 V

excessive to 150 V.

2. Run takes unusually a. Ion depletion in running a. Prepare and use fresh

long time. buffer (lower tank) buffer.

b. Running buffer too b. Check buffer protocol

concentrated. and dilute buffer if

necessary.

3. Changes in protein a. Ion depletion in running a. Prepare and use fresh

mobility or band buffer (lower tank) buffer.
sharpness.

4. SDS is precipitating. a. Running buffer is too cold. a. Set the refrigerated

circulator to maintain a
buffer temperature of
18–20 ºC.

5. Vertical streaking of a. Sample overload or a. Dilute sample,

proteins. protein precipitation selectively remove

predominant protein in the
sample, or reduce the
voltage by about 25% to
minimize streaking.

b.The ratio of SDS to protein

should be enough to coat
each protein molecule,
generally 1.4:1. It may
require more SDS for some
membrane samples.

c. Ensure sample is suspend-

ed completely in sample
buffer prior to loading.

6. Lateral band spreading a. Diffusion out of the a. Minimize the time

wells prior to turning between sample
on the current application and power

start up.

b. Ionic strength of sample b. Use same buffer in sample

lower than that of gel as in gel or stacking gel

7. Skewed or distorted a. Salts in sample a. Remove salts by

bands dialysis, desalting column,

etc.

8. Lanes constricted at the a. Ionic strength of sample a. Desalt sample and

bottom of the gel. higher than that of neighboring samples.

surrounding gel.

9

Problem Cause Solution

9. End gels are running a. Buffer is warmer at the a. Ensure the stir bar is freely

faster than the center ends of the cell than the rotating to maintain a
gels. center. constant buffer temperature.

10. Sample not migrating a. Tape is still on the bottom a. Remove the white tape

of the gel. prior to electrophoresis.

b. No electrical connection. b. Check continuity of

electrode wires in lid and
tank.

Section 5
Product Information and Accessories

Catalog
Number Description

Criterion Dodeca Cell and Accessories

165-4130 Criterion Dodeca Cell

165-4135 Lower Electrode Assembly with Platinum Wire

165-4104 Replacement Drain Line

165-4136 Replacement cooling coil, includes connector tubing

165-2948 Replacement power cables

165-4137 Replacement lid

Power supply

165-5052 PowerPac 200 power supply, 100/120 V

165-5053 PowerPac 200 power supply, 220/240 V

165-5062 PowerPac shelf; attaches to the underside of a shelf and holds the

PowerPac 200

Premixed Electrophoresis Buffers

161-0772 10x Tris/Glycine/SDS,5L

161-0757 10x Tris/Glycine,5L

161-0760 10x Tris/Tricine/SDS,6x1L

161-0770 10x Tris/Boric Acid/EDTA,5L

161-0773 50x Tris/Acetic Acid/EDTA,5L

10

Section 6
Warranty Information

The Criterion Dodeca Cell is warranted for 1 year against defects in materials and work­manship. If any defects should occur during this warranty period, Bio-Rad Laboratories will
replace the defective parts without charge. However, the following defects are specifically
excluded:

1. Defects caused by improper operation.

2. Repairs or modifications performed by anyone other than Bio-Rad Laboratories or their

authorized agent.

3. Damage caused by accidental misuse.

4. Damage caused by disaster.

5. Common replacement parts including platinum wire and power cables.

6. Damage caused by the use of organic solvents.

For inquiries or to request repair service, contact your local Bio-Rad office.

Warranty Information

Model

Catalog Number

Date of Delivery

Serial Number

Invoice Number

Purchase Order Number

11

Bio-Rad

4006197 Rev A

Laboratories

Life Science
Group

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